Non-Defined Subdomains

How can I force my website to not function when there is a subdomain that is not in the dns.

ex//

test.domain.com <- invalice
mail.domain.com <-valid

how can I force test.domain to go to domain.com is this a dns issue or a server setting?

cstormerAsked: 2011-03-05

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LVL 9

jeremycrussellConnect With a Mentor Commented: 2011-03-07

Ok, so, unless you have some type of DNS record to cover all the possible <text>.domain.com the, when they are entered, they won't resolve.

To accomplish what you mentioned, you could do this by having A or CNAME records for your "valid" FQDNs, and then use a wildcard A record, assuming your DNS provider supports that.

Then, you could use some rewrite rules send "invalid" FQDNs to a particular page.

For instance, with Apache and mod_rewrite.

RewriteEngine On
RewriteCond %{HTTP_HOST} !^domain.com$
RewriteCond %{HTTP_HOST} !^www.domain.com$ (you would have a rewrite condition for all your "valid" subdomains.
RewriteRule ^(.*) http://domain.com/$1

LVL 31

farzanjCommented: 2011-03-05

Try iptables

If the entry is not in the DNS, it should not get a reply.

Block Invalid

iptables -A -p tcp -d test.domain.com --dport 80 -j DROP

Open in new window

Forwarding to another domain

iptables -t nat -A PREROUTING -d test.domain -p tcp --dport 80 -j DNAT --to domain.com

Open in new window

cstormerAuthor Commented: 2011-03-07

A follow up question is which is better from an SEO point of view?

Is it better to make all the sites with broken links that point to my domain still function if someone clicks on the link or Google comes in off that link... by having them redirect to the domain.com version.

Basically..

badtext.domain.com/page/page.php = .domain.com/page/page.php

Is that more of a URL rewrite... issue or should i just make anything that does not point to the right domain not work..